Shelf Life of PMK Pyro Working Solution

[scott_killian1]

I own Gordon Hutching's excellent book, The Book of Pyro, but I

can find no reference to the shelf life of PMK Pyro WORKING

solution (plenty of info out there on stock solution). I've noticed

that it gets increasingly dark as it oxidizes, but still have no clear

information on actual effective shelf life. Anyone have any

experience with this? Thanks.

[sergio_ortega6]

Scott,

 

I don't have the Pyro book in front of me, but I believe that Hutchings states that the working solution should be used shortly after combining the A and B stock solutions with water. I understand the working solution does not have any shelf life.

[jorge_gasteazoro5]

I did an experiment once and waited 30 minutes once the developer was mixed. I developed a sheet exposed at Zone V....it was terrible. The developer looses energy very fast. So I would recommend you use it right away once mixed.

[doug_theall2]

I only mix as much as I am going to use. My wife is a nurse and she found me a a shuringe (spelling) to measure it by millimeters. Works great. Do the math and only mix what you are going to use right then.

Good luck,

Doug

[david_goldfarb]

Yes, mix and use it immediately.

[ken_miller4]

Not to hijack the thread or anything, but I use a child's medicine measuring spoon. It's measured in ml's, which makes it very easy for measuing out solution for developing. I use an eye-dropper to pull the solution out of the bottle. I replace the extracted solution with marbles. Make sure you rinse the dropper well before moving on to the next solution, else you'll contaminate it.

 

When I do a batch of 4 4x5 sheets in my tubes (75ml in each tube) using Pryrocat-HD, I mix up 300ml of distilled water, plus 3ml of part A, and 3ml of part B. The spoon holds 10ml, so it's just perfect.

 

It works for me.

[scott_killian1]

Thanks, everyone. Looks like I was making-up far too much

working solution - I had no idea that it went bad that quickly. As

usual, everyone's posts were a huge help.